Fair Value Measurements - Estimated Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 13,658,585	$ 16,583,000	$ 15,184,395	$ 10,288,853
Securities held to maturity	1,946,428	1,749,179
Loans, net	16,496,394	16,087,731
Deposits	45,601,765	42,695,696
Federal funds purchased	43,200	25,925
Repurchase agreements	1,664,685	2,740,799
Junior subordinated deferrable interest debentures	123,040	123,011
Subordinated notes	99,256	99,178
Carrying Amount [Member] \| Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	13,658,585	16,583,000
Securities held to maturity	1,946,428	1,749,179
Cash surrender value of life insurance policies	189,823	190,139
Accrued interest receivable	194,049	179,111
Deposits	45,601,765	42,695,696
Federal funds purchased	43,200	25,925
Repurchase agreements	1,664,685	2,740,799
Junior subordinated deferrable interest debentures	123,040	123,011
Subordinated notes	99,256	99,178
Accrued interest payable	6,059	3,026
Carrying Amount [Member] \| Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	16,496,394	16,087,731
Estimated Fair Value [Member] \| Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	13,658,585	16,583,000
Securities held to maturity	1,828,515	1,809,143
Cash surrender value of life insurance policies	189,823	190,139
Accrued interest receivable	194,049	179,111
Deposits	45,584,113	41,343,426
Federal funds purchased	43,200	25,925
Repurchase agreements	1,664,685	2,740,799
Junior subordinated deferrable interest debentures	123,712	123,712
Subordinated notes	99,626	111,430
Accrued interest payable	6,059	3,026
Estimated Fair Value [Member] \| Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	$ 16,126,497	$ 16,079,454

Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Carrying amount as of the balance sheet date of amounts which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity.

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Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

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Amount of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

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Amount of interest payable on debt, including, but not limited to, trade payables.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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